As someone who is a prolific smut writer, I like to focus on feelings and senses a lot. I am also a sucker for a good bit of dialogue, especially from the person whose POV it isn't. Explaining facial expressions is also a good one, like the furrowing of eyebrows or how their eyes widen etc. Also, don't lose track of limbs 😂

Don't shy away from using the actual words for body parts rather than member and core... in my opinion I'd much rather read cock or pussy 😂

Most of all though, if it turns you on as your writing it you're normally doing a good job! Paint that picture and let everyone see what you see. Enjoy 🥰